Rotary earth drills are commonly used in drilling operations, especially for drilling holes and conducting subsurface soil testing. These drills utilize drill bits to cut away soil and rock which is then removed from the drilling area up the shaft. Frequently, drill bits break, or lose their edge with age and use, and when they cease to be effective in removing soil or rock, the drilling operation must be stopped, the drill removed and the bits replaced. Therefore, it is desirable to utilize drill bits that retain their edge for the longest possible duration to reduce the occurrence of bit replacement.
Additionally, after drill bits have been used in drilling operations, it is often difficult to remove them from the heads. This is especially true because it is desirable to perform replacements on site, which is typically in a remote area with limited resources. Some mounting methods have been used that simplify replacement, but result in an increased incident of drill bits coming detached from the head during drilling operations.
Accordingly, a continuing search has been directed to the development of tools that are more rugged and durable that need to be replaced less frequently, drill earth with greater efficiency, and that can be replaced easily on site, when necessary.
The present invention is directed to a rotary earth auger that utilizes drill bit assemblies to which both blades and finger bits are attached. The configuration and arrangement of the bits improves cutting efficiency, increases wear life and reduces the likelihood of the bits breaking during operation.
The individual drill bit assemblies have a self-locking hook configuration and are retained on the auger head by means of a unique sandwich mechanism to reduce incidents of the drill bit assembly becoming detached from the auger during drilling operations. Additionally, the drill bit assemblies are attached to the auger using an attachment method that resists rusting when the drill is in use, which makes the drill bit assemblies easier to remove from the drill when it is necessary to replace the bits.
The invention is a hollow auger head assembly for penetrating geological formations, comprising a hollow auger head configured such that it can be secured to a conventional auger used for drilling, and at least two drill bit assemblies secured to the hollow auger head. Each drill bit assembly comprises a drill bit body having a means of attachment, at least one finger bit secured to the underside of the drill bit body, and at least one blade secured to the front edge of the drill bit body.
The foregoing has outlined rather broadly the features and technical advantages of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter which form the subject of the claims of the invention. It should be appreciated by those skilled in the art that the conception and the specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims.